


Butt Bot Battle

by emissaryofrainbows



Category: NieR: Automata (Video Game), Undertale (Video Game)
Genre: Anal Sex, Ass Play, Crossover, F/M, Gratuitous Smut, M/M, Multi, POV Second Person, Reader-Insert, Rimming, Shameless Smut, Smut
Language: English
Status: Completed
Published: 2018-09-16
Updated: 2018-09-16
Packaged: 2019-07-13 04:36:11
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,549
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16010423
Author URL: https://archiveofourown.org/users/emissaryofrainbows/pseuds/emissaryofrainbows
Summary: Mettaton and 2B have a disagreement over who has the best robot butt in video games. They leave it up to you, the reader, to decide, and they’re both willing to do just about anything to win.





	Butt Bot Battle

2B bent over, lifting up her skirt to expose her fat ass, and the plump thighs beneath it. The pale, perfectly smooth skin was slightly slick and shiny, either from water, sweat, or oil that had been intentionally applied, it was difficult to tell. The globular cheeks spilled out from her uniform, somehow able to avoid sagging despite their obvious weight. She slapped it lightly; the supple, fatty flesh jiggled noticeably at her touch. Her lips were pillowy, and her stark white hair complimented the blackness of her frilly uniform well.

“Not bad, darling,” Mettaton said. Always the showman, his voice was even more exaggeratedly sultry than usual. “But anon already knows that my butt is far better, right?”

Mettaton leaned towards your face, like he was going in for a kiss, before pulling back with a chuckle. “I know my face is gorgeous, but you’re clearly more interested in my other end.”

If 2B wasn’t wearing a blindfold, she would be seen rolling her eyes. Mettaton turned around, and unlike 2B, who kept her ass at a respectable distance, he parked his rear mere inches away from your face.

Mettaton’s ass wasn’t as bodacious as 2B’s. Instead, it was perfectly sculpted, and athletic, packed tightly underneath his black, rubbery exterior. The apple-shaped cheeks sat above his thighs, which were thick and muscular as well. His hips were wide, almost as wide as his female competitor’s, with long, shapely legs. As with 2B, his lips were alluringly kissable, coated in a layer of perfectly-applied glossy lipstick. His entire body was lithe, a heart-shaped belt partly covering his flat, toned tummy.

“Go ahead, touch,” Mettaton said playfully. After only a moment of hesitation, you placed your hand against one of the flawlessly curved cheeks. His ass was hard, densely packed with muscle, or some synthetic equivalent. Despite its firmness, it still had a bit of give. You sink your fingers into it slightly, before gliding your fingertips across the perfect curve of his obsidian bottom.

Mettaton pulled away, turning back around, and then towards his rival. “I think anon’s had enough for now. It’s your turn~”

2B nodded, and once again, you were treated to an ass being thrust dangerously close to your face. Now that 2B’s ass was in motion, it was hardly ever still; not a moment passed where it didn’t jiggle or tremble like it was caught in an earthquake.

“You can touch it,” she said coldly. You prod a cheek curiously with your finger. It sinks into her flesh far deeper than it did with Mettaton’s, a few centimeters at least.

“It’s designed to simulate the warmth and softness of real human flesh,” she said. You disagree, but only because hers was significantly softer and warmer than most non-android asses you’ve encountered. “It’s so much better than a rigid, hard one, don’t you agree?”

“Ooo, catty,” Mettaton said. “Sure, some cushioning is nice, but I’m sure anon would like a tight, muscular ass better when it’s on top of him.”

“What do you mean?” 2B said. Mettaton ignored her.

“Anon, lay down here,” he said, pointing to an unoccupied spot on the ground. You do as instructed.

Mettaton stood over your prone body, before planting his firm tush directly onto your face! You can feel the taut, latex-covered cheeks, pushed hard against you by the considerable weight of Mettaton’s metal body.

“See, you couldn’t do this to anon without crushing them, you big fatass~”

Mettaton’s ass may have been round, but it was relatively contained, giving you just enough room to breathe comfortably. Mettaton wiggles his ass back and forth on top of you, stopping just short of straight-up grinding on your face. You can feel his puckered hole hovering above you, barely a millimeter away from your mouth. Almost without thinking, you stick out your tongue, pushing it up against his ring.

“Ooo-oooooooh!” Mettaton moaned, almost musically. He adjusted himself, forcing his ass even closer towards you, as an indication that he wanted more. You happily oblige.

Your run the tip of your tongue all around the exterior of his hole, which drives him wild. Tired of teasing him, you penetrate his ass with your tongue, pushing it in as deep as it can go.

Mettaton bit his lip, eyes rolling into the back of his head, practically drooling. His glamorous exterior had fallen away; he was a shameless butt-slut now.

You pull your tongue in and out, alternating between prodding and licking his hole. There was a subtle, but addicting sweetness to his ass, that compelled you to slurp away at it even more, as if you needed any more motivation.

“F-fuck, I think I’m-I’m going to-”

Before Mettaton could finish, his body was jerked away from yours. 2B had pushed him off of you, right before he reached his climax. Mettaton was left an exhausted, confused mess, still desperate to get off. 2B took advantage of his daze, to make you a proposition.

“You have my permission to fuck my ass,” she said. Her formal phrasing was a bit of a turn off, but that was usual for 2B. You rise to your feet, your cock painfully, erect, throbbing audibly from when you were tongue-deep in Mettaton’s asshole.

2B stripped naked with characteristic efficiency, removing every article of clothing, save her mask. You get to see her from the front for a moment. Her breasts were fairly large, and perky, with pale-pink nipples. Her pussy had a small, well-groomed patch of white pubic hair above it, and was otherwise hairless. As nice as she looked from the front, it was just a mere appetizer compared to her backside.

She bent over, and pulled her cheeks apart, giving you access to the trembling hole that lay between those twin mountains of ass flesh.

“Go ahead,” she said. “There’s no need to hold back, I come pre-lubricated.”

2B wasn’t lying. Your cock glided effortlessly into her ass, her hole sucking around it greedily, not wanting to let it go. You only see 2B’s face for a moment as you withdraw, but the brief glance makes it clear that she’s putting all of her effort into not looking like she’s enjoying herself. You decide to make that more difficult for her.

You pump your cock in and out of her, as hard and fast as you can, her soft as providing a perfect cushion. You gradually begin to build up a rhythm, building up speed with each thrust. You can just barely hear 2B’s stifled moans over the sound of your hips slapping repeatedly against her jiggling ass.

2B’s ass is so tight, and her fat cheeks fell so good pressed around your erection. You feel like you can’t handle it for another second!

Before you can cum, you find yourself interrupted again, this time by Mettaton. He managed to fight his way out of his sexual haze, now sporting a tenting erection from his unsatisfying near-orgasm. You can see a single bud of precum, trapped around the tip of his cock by the skintight rubber.

“No fair!” Mettaton said. “Once anon cums, they’ll be too tired to fuck me.”

“That’s the plan,” 2B said sardonically.

“Well, it’s against the rules. It’ll only be fair if we both make anon cum at the same time.”

2B turns around, to see you nodding eagerly at the proposition.

“Well, anon seems to agree. Let’s do it.”

2B pulls away from you, leaving your boner tragically unsatisfied. Fortunately, this gives you some time to recuperate, to give yourself some more stamina so you don’t just cum immediately.

“So, how are we going to do this?” she asked.

Mettaton tapped his chin. “Maybe we could have anon grind his cock between both of our asses at once?”

You find this plan very agreeable.

Mettaton and 2B stand on either side of your cock, facing away from you, asses level with your throbbing shaft.

“On three,” 2B said.

“Three…two…one.”

2B and Mettaton pressed their asses together simultaneously, sandwiching your cock in between the two flawless mechanical posteriors. They moved their asses up and down, and side to side, grinding against your member.

Their asses complemented each other perfectly, Mettaton’s firm ass helped to smush your cock even deeper into 2B’s squishy cheeks. And, likewise, 2B’s cushiony rump forced yours against Mettaton’s solid bottom, as it rubbed its way up and down your shaft.

2B’s breasts heaved as she grinded against you. The bubble of precum at the tip of his cock began to swell, and bobbed up and down along with his dick, and the rest of him.

“So, anon, which one do you like better?”

“Why even bother asking? You already know it’s me.”

You simply can’t take it anymore. Your cock erupts, spurting out an enormous load, to match your immensely satisfying climax. Both pairs of butts end up coated in a considerable amount of your cum, coating their cheeks, dripping down into their cracks.

The pleasure hits you like a wave. The combination of your overwhelming orgasm, and plain old physical exhaustion causes you to pass out. Mettaton and 2B dismount from your cock, and now stand curiously over your unconscious body.

“Does this mean I won?” Mettaton asked.

“We’ll call it a tie,” 2B replied.


End file.
